Cognomen Thongthaeng (Thongthaeng 
) , throughout the world, is a very rare last name. The family name Thongthaeng is characteristic of Thailand, where it is a very rare surname, and Canada, where it is an extremely rare surname. Very seldom, Thongthaeng is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Thongthaeng | Canada, Thailand |